Democrats are on the p.r. offensive against the House Select Committee on Benghazi — doing their best to smear its work ahead of Hillary Clinton’s Oct. 22 testimony.

Great for Clinton. For the American people — particularly the families of the four officials, including Ambassador Chris Stevens, killed in the terrorist attack — not so much.

Majority Leader Kevin McCarthy gave the Dems some ammo with bumbling remarks the other week; more came over the weekend from a fired committee employee.

McCarthy’s comments suggested that the committee was set up expressly to undermine Clinton’s campaign. That was music to Democratic ears — but it just isn’t true.

Sure, the probe — conducted almost entirely behind closed doors, out of the glare of publicity and partisan showboating — has lasted 18 months. But that’s largely because the State Department continues to stonewall, withholding thousands of documents.

Plus: New information — like Hillary Clinton’s e-mails, many of them classified and Benghazi-related — is still being uncovered.

Democrats claim the committee is just repeating work done by prior investigations. Funny: Not one of those probes noticed the huge fact that State had no records of Clinton’s e-mails for her entire time as secretary.

Among those bumbling probes was State’s own “independent” review — the findings of which, the nation learned recently, were altered by Clinton’s top aide, Cheryl Mills.

Note, too, that Mills herself, after her private interview before the committee, praised the panel and Chairman Trey Gowdy for their “professionalism” and “respect.”

Yes, that ex-employee now says he was fired in part because he objected to the committee’s targeting of Clinton. But as Gowdy noted, he only made that claim after McCarthy’s remarks. In fact, the staffer was himself reprimanded for “improperly” focusing on Hillary “and instructed to stop.”

The bottom line: Americans still don’t know the full story of what happened that night four years ago in Benghazi. Until they do, Democrats should stop obstructing and start cooperating.